vssh

vssh.fish

#!/usr/bin/env fish

# add the following line to ~/.config/fish/completions in order to add hostname completion to the script
# complete -x -c vssh -d "Remote" -a "(__fish_complete_user_at_hosts)"

function get_gateway --argument addr
   route -n get -net $addr | awk '/gateway/ { print $2 }'
end

function get_global_protect_interface_ipaddr_from_config
   # parse global protect settings, extract preferred interface ips
   # than iterate interfaces and try to find which interface belongs to this ip
   /usr/libexec/PlistBuddy -c "print 'Palo Alto Networks':GlobalProtect:PanGPS" /Library/Preferences/com.paloaltonetworks.GlobalProtect.settings.plist | \
       awk -F'=' '/PreferredIP_/ { print $2 }' | \
       tr -d '[:blank:]' | \
       xargs -I {} fish -c "ifconfig -a | awk '/inet {}/ { print \$2 }'"
end

function get_global_protect_interface_ipaddr_from_install_script
   sudo awk '/\/sbin\/ifconfig [^ ]+ [0-9]/ { print $3 }' \
       /Library/Logs/PaloAltoNetworks/GlobalProtect/network/config/itf-install.sh
end


function add_static_route --argument addr --argument gateway
   echo "adding a static route from $addr to $gateway"
   sudo route -n add -net $addr $gateway > /dev/null
end

function delete_static_route --argument addr
   echo "deleting static route for $addr"
   sudo route -n delete -net $addr > /dev/null
end

set remote (ssh -G $argv 2>/dev/null | awk '/^hostname/ { print $2 }')

# get the ip address of the vpn device
set gateway (get_global_protect_interface_ipaddr_from_config)

if test -z "$gateway"
   echo "need root privileges in order to find the vpn gateway"
   set gateway (get_global_protect_interface_ipaddr_from_install_script)
end

if ! ifconfig -a | grep "$gateway" &>/dev/null
    echo "couldn't find any interface bound to $gateway"
    echo "maybe the vpn client is not connected?"
    exit 1
end
   
# get the hostname that ssh is going to use
if test (get_gateway $remote) != "$gateway"
   echo "need root privileges in order to add a static route"
   delete_static_route $remote || exit 1
   add_static_route $remote $gateway || exit 1
end

ssh $argv

My use case was a little different but this was very helpful. Thanks Oded!